Optical communication systems often employ one or more WDM (Wavelength Division Multiplexed) optical links that typically include a transmitter in optical communication with a receiver. The transmitter generates multiple modulated light signals that are received by the receiver. The receiver demultiplexes the modulated light signals and, in some instances, uses the demultiplexed light signals to generate electrical signals.
The receiver and transmitter are each positioned in an atmosphere with an operational temperature range. For instance, the receiver and transmitter can each be positioned in a different atmosphere and the operational temperature of that atmosphere can vary over a wide range of temperatures. However, the optical components on a transmitter can respond differently to changes in temperature. As a result, a transmitter that functions very well at a temperature where the operational wavelengths of the different components are matched can become highly inefficient at a different temperature. Further, the receivers are associated with the same difficulty.
To make matters worse, the temperature of the atmosphere in which the receiver is positioned can be very different from the temperature of the atmosphere in which the transmitter is positioned. These differences in temperature means that the operational wavelengths of the components on the transmitter have shifted differently than the operational wavelengths of the components on the receiver. As a result, the different temperature of the transmitter and receiver cause further drops in the efficiency of the optical link.
The above problems have been addressed by using a common temperature controller to maintain the transmitter and receiver at a defined temperature. For instance, if the transmitter and receiver are positioned in different atmospheres that each has an operational temperature range of 0-70° C., the transmitter and receiver can be maintained at around 80° C. with the use of heating elements and the operational wavelengths of the components on the transmitter and receiver can be configured to match at 80° C. As a result, the transmitter and receiver efficiently work together at 80° C. and the temperature of the transmitter and receiver does not substantially shift away from 80° C. Alternatively, a TEC (thermo electric cooler) device can be used to maintain the transmitter and receiver at temperatures between 0-70° C., for instance at 55° C. Accordingly, the problems associated with temperature shifts of the transmitter and/or receiver are eliminated. However, the energy requirements needed to keep a transmitter and receiver at these temperature levels are very large and not practical when large numbers of optical links are desired. As a result, there is a need for a more energy efficient optical link.